Endocrine effects of GnRH agonist application to early pregnant gilts

The hypothesis of the present study was that a GnRH agonist application at early pregnancy would alter the pattern of the key reproductive hormones LH and FSH, and subsequently that of estradiol (E2) and especially progesterone (P4), and improve the conditions for embryo survival in early pregnant gilts. Therefore, the endocrine effects of a GnRH agonist (GnRHa) application to gilts (n=11 GnRHa treated, n=9 saline Controls) were studied in blood samples from the Vena cava caudalis. GnRHa injected on Day 12 after insemination induced elevated (P<0.01) LH and FSH levels for at least 180 min. However, subsequent LH concentrations were not altered up to Day 21 of pregnancy. LH pulse number, estimated in 6-h period samples on Days 13, 15 and 17, was not influenced by treatment and pregnancy. LH pulse amplitude was decreased (P<0.05) on Days 13 to 17 in pregnant gilts of both groups, but not in nonpregnant animals. In pregnant GnRHa-treated gilts, the basal LH level was elevated compared with the Controls (P<0.01). Additionally, differences (P<0.05) in basal LH were present between the pregnant and nonpregnant animals. The P4 and E2 secretion pattern was not affected by GnRHa. P4 concentrations increased (P<0.01) from Day 10 to Day 14 regardless of the treatment. P4 revealed a pulse-like pattern, but without a definite relation to the LH pulse characteristics. Also, pregnancy rate (73 vs. 67%) and the number of fetuses (12.8 ± 2.3 vs. 11.6 ± 2.3) were unaffected in the treated and Control gilts, respectively. The present study did not confirm the initial hypothesis that a GnRHa-mediated LH effect could alter ovarian steroid secretion and favorably support early embryo development and pregnancy outcome.     

New understanding of immunological mechanisms

The understanding and importance of antigen-specific immune responses after vaccination has completely changed in recent years. In the past, the focus for monitoring a vaccine-specific immune reaction was principally on the humoral branch of the immune system. The efficacy of vaccines, as assessed by the induction of protective immunity was mainly correlated with antibodies and antibody-titers. However, this correlation often failed and other parts of the immune system had also to be considered: namely, the innate immune system and the cellular branch of the antigen-specific immune system. With regard to vaccines, the innate immune system plays its main role in the effective activation of the antigen-specific immune response, in antigen-uptake and antigen-presentation. The dendritic cells (DCs) are the most important antigen presenting cells which present processed protein antigens (peptides) through MHC-molecules: MHC-class I, for the presentation of endogenous synthesised antigen; MHC-class II for exogenous antigen. Activation of DC leads to an enhanced production of cytokines and chemokines, to an up-regulation of co-stimulatory and activation molecules and also molecules for cell-cell interactions, e.g. interactions with cells of the antigen-specific immune system. T lymphocytes are the effector cells of the cellular branch of the antigen-specific immune system. They act either as MHC-class I-restricted cytolytic T lymphocytes (CTL) or as MHC-class II-restricted T-helper cells providing support for B lymphocytes (T(H)2) and the cellular part of the antigen-specific immune system (T(H)1). In order to achieve effective vaccination, the activation of all T-cell subpopulations is of advantage, but more important is the generation of antigen-specific memory T and B lymphocytes. In addition to these 'generic' immunological factors which are essential for the design of more efficacious vaccines, our detailed knowledge about feline and canine immune reactions after vaccination, which is still poor, has to be improved.     

Interferon-gamma response of PBMC indicates productive pseudorabies virus (PRV) infection in swine

In Chinese Meishan/German Landrace cross-bred swine F2 generation interferon gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) was determined directly ex vivo at different time points after survival of a virulent pseudorabies virus (PRV) infection. This reactivity was compared with the reactivity of na?ve PBMC. Significant IFN-gamma production was determined in ELISA and ELISPOT only after in vitro PBMC re-stimulation with PRV and not with the closely related bovine herpesvirus BHV-1. The PRV-specific IFN-gamma secretion from re-stimulated PBMC showed high levels 6 days after infection, before the presence of serum antibodies, and it persisted at a high level over a 3 months period. The response of a group of eight piglets infected intranasally with PRV varied. Only two animals showed the expected typical fever response. PRV specific IFN-gamma production by PBMC clearly indicated that infection had occurred. Early significant IFN-gamma production by primed PBMC turned out to be a reliable and specific ex vivo marker for cellular response against productive PRV infection in swine before antibody formation.     

A design for studies on cognitive bias in the domestic pig

Studies on consequences of affect on cognitive processing (cognitive bias) seem to provide proxy measures of the valence (positive/negative) of affective states. This article presents a pilot study testing a design for studies of judgment bias we adapted to the specific needs and abilities of domestic pigs. We used a spatial judgment paradigm, in which subjects learned to discriminate a food rewarded from an unrewarded position of a goal box during a training period, and then were tested for their responses to 3 equidistant intermediate probe positions during a testing period. After the training period, half of the subjects were repeatedly isolated from their social group to manipulate their affective state. Subjects learned the required discrimination task (positive vs. negative stimulus) and showed consistent differences in approach latencies toward and exploration of stimuli of different valence. Hence, the subjects' expectations could be inferred from their behavior. However, repeated social isolation had no effect on judgment of ambiguous stimuli and on both basal and test-related cortisol levels. In conclusion, the spatial judgment approach seems to provide a useful tool to detect and discriminate diverse affective states in domestic pigs based on their responses to graded ambiguous stimuli.     

The Schmallenberg virus epidemic in Europe—2011–2013

During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006–2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases.     

Goat paratuberculosis in Chile: first isolation and confirmation of Mycobacterium avium subspecies paratuberculosis infection in a dairy goat.

In October 2004, 41 goats > 2 years old from a Saanen dairy goat herd located in Purranque County, 10th Region, Chile, were sampled and tested for paratuberculosis. While collecting samples it was observed that several goats were thin and emaciated. One goat was sufficiently debilitated to warrant humane euthanasia. This animal was brought to the Veterinary School at the Universidad Austral de Chile for necropsy. The goat selected for necropsy was a 12-year-old doe. The animal showed classical clinical signs of caprine paratuberculosis: emaciation despite willingness to eat, dry and rough hair coat, and no evidence of diarrhea. Gross pathology and histopathology of the necropsied goat were consistent with paucibacillary paratuberculosis. Bacteriology, serology, and PCR confirmed the diagnosis. This is the first published report of goat paratuberculosis in Chile confirming a case of caprine paucibacillary paratuberculosis.     

Intraepithelial but not lamina propria lymphocytes in the porcine gut are affected by dexamethasone treatment

It is well established that glucocorticoids are key regulators of the immune system and act as immunosuppressive agents in high concentrations. In the pig, effects on the gut immune system and trafficking of lymphocytes between tissues and blood plasma were not investigated so far. Twelve pigs of 70 kg were fed 0.4 mg portions of dexamethasone (Dexa) twice daily for 9 days or remained untreated (controls) and were sacrificed for tissue collection at the end of Dexa treatment. Another six pigs with jugular vein catheters were left untreated for 7 days (control period) and then received Dexa for 9 days. Blood was drawn twice during the control period and at days 3, 6 and 9 of the Dexa period for characterization of peripheral blood leukocytes. Cells were obtained from thymus, mesenteric lymph nodes, jejunal mucosa and Peyer's patches. Lymphoid cells from gut tissue were isolated from two fractions: the EDTA-fraction, containing the intraepithelial lymphocytes (IEL), and the Collagenase-fraction, containing the lamina propria lymphocytes (LPL). In all samples, cell counts and phenotypic characterization of cells by flow cytometry (FCM) were performed. In thymus, Dexa led to a more than 90% reduction of the absolute cell number, which was mainly found in the CD4+CD8+ subpopulation. Dexa effects on lymphocytes from mesenteric lymph nodes were less severe (50%) and led mainly to a decrease (71%) of B-lymphocytes. The number of lymphocytes in the EDTA-fraction (IEL) of the jejunal mucosa decreased significantly by 56% in the Dexa-treated animals compared to the controls, whereas the number of lymphocytes in the Collagenase-fraction (LPL) decreased only moderately. In the Peyer's patches, a decreasing tendency in the number of lymphocytes in the EDTA-fraction was observed which, however, was not significant. In blood, monocytes and granulocytes were significantly increased in an order of 60%. The data show that supraphysiological amounts of Dexa remarkably reduce cell numbers in thymus and also in the intraepithelial compartment of the jejunal mucosa and ileal Peyer's patches. In blood, a notable homeostasis was observed for several leukocyte populations whereas both monocytes and granulocytes increased.     

Confirmation of spatial patterns and temperature effects in Bluetongue virus serotype-8 transmission in NW-Europe from the 2007 reported case data

Two separate analyses were carried out to understand the epidemiology of Bluetongue virus serotype 8 (BTV-8) in 2007 in North West Europe: First, the temporal change in transmission rates was compared to the evolution of temperature during that season. Second, we evaluated the spatio-temporal dynamics of newly reported outbreaks, to estimate a spatial transmission kernel. For both analyses, the approach as used before in analysing the 2006 BTV-8 epidemic had to be adapted in order to take into account the fact that the 2007 epidemic was not a newly arising epidemic, but one advancing from whereto it had already spread in 2006. We found that within the area already affected by the 2006 outbreak, the pattern of newly infected farms in 2007 cannot be explained by between-farm transmission, but rather by local re-emergence of the virus throughout that region. This indicates that persistence through winter was ubiquitous for BTV-8. Just like in 2006, we also found that the temperature at which the infection starts to spread lies close to 15 °C. Finally, we found that the shape of the transmission kernel is in line with the one from the 2006 epidemic. In conclusion, despite the substantial differences between 2006 and 2007 in temperature patterns (2006 featured a heat wave in July, whereas 2007 was more regular) and spatial epidemic extent, both the minimum temperature required for transmission and the transmission kernel were similar to those estimated for the 2006 outbreak, indicating that they are robust properties, suitable for extrapolation to other years and similar regions.